Method for cutting rounded glass blanks



y 1950 D. ECHTER ETAL METHOD FOR CUTTING ROUNDED GLASS BLANKS Filed June30, 1948 Patented May 16, 1950 METHOD FOR CUTTING ROUNDED GLASS BLANKSDavid Echter and Ernest B. Paul, New Haven, 001111., assignors to TheEchter-Paul Corporation, New Haven, Conn., a corporation of ConnecticutApplication June 30, 1948, Serial N0. 36,014

4 Claims. 1

The present invention relates to improvements in methods for cuttingglass and relates more particularly to methods for cutting a pluralityof rounded (circles, ovals, etc.) blanks from sheets of glass such, forinstance, as blanks which are useful as crystals for clocks, watches andother instruments. Heretofore it has been the general practice to scribeupon the surface of a sheet of glass a plurality of incisions oroutline-cuts which constitute incipient fractures. Such prior practice,however, has located the said outline-cuts markedly spaced from eachother so that an uncut portion of the sheet of glass intervened betweeneach blank of an adjacent pair of blanks. The described practice hasrequired the further cutting of the portions of the sheet outside of thesaid blanks in order to complete the incipient fractures into completefractures and to free the said blanks from the surrounding portions ofthe sheet. This procedure has been slow and expensive and has produced awasteful number of defective or broken blanks.

We have discovered that the major portion of the defects of thedescribed prior practice may be obviated by the simple expedient ofcausing the rounded outline-cuts defining one rounded blank tosubstantially coincide with or be superimposed upon a portion of therounded outlinecut defining an adjacent blank, as will be apparent fromthe following description considered in conjunction with theaccompanying drawings.

One of the main objects of the present invention is to provide asuperior method for cutting rounded glass blanks whereby over-all costsare kept at a minimum. Another object of the present invention is toprovide a superior method of the character described whereby a pluralityof rounded blanks may be produced from a sheet of glass with a minimumnumber of cuts.

A further object of the present invention is to provide a superiormethod for cutting rounded glass blanks whereby a minimum number ofdefective blanks is produced.

A still further object of the present invention is to provide a superiormethod of the character described which is suitable for being carriedout by automatic machinery.

With the above and other objects in view, as will appear to thoseskilled in the art from the present disclosure, this invention includesall features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. .1 is a face view of an elongated sheet of glass from which aplurality of rounded blanks may be produced in accordance with thepresent invention;

Fi 2 is a similar view but showing the said sheet after the same hasbeen provided with a plurality of .rounded outline-cuts to produce inthe said sheet the desired incipient fractures;"

Fig. 3 is a broken sectional perspective view taken on the line 3-3 ofFig. 2, but on a larger scale;

Fig. 4 is a transverse sectional view taken on the line 4-4 of Fig. 2,but on a larger scale, and showing the effect of flexing theedge-portions of the sheet to complete or "open the incipient fracturesand permit the separation of the said edge-portions from the blanks;

Fig. 5 is a face view of the parts of the sheet of glass after the samehas been provided with the plurality of outline-cuts and has been flexedto open-the incipient fractures and with the resultant parts shown asseparated, for clarity of illustration;

Fig. 6 is a perspective view of one of the resultant blanks; and

Fig. 7 is a face view similar to Fig. 2 but showing the extra cutsrequired in accordance with the prior general practice.

A preferred mode of carrying out the method of the present inventioncomprises providing an elongated sheet or strip of glass or equivalentmaterial l0 indicated in Fig. 1, which sheet is preferably of a widthslightly exceeding the width of the blanks to be cut therefrom and of alength substantially equal to the total length of the desired pluralityof blanks.

As is indicated in Figs. 2 and 3, there is scribed upon the face of thesheet ID a plurality of rounded outline-cuts H which constituteincipient fractures and each of which outlines a complete blank I! whichit is desired to produce. In the instance shown, eight blanks l2 areprovided for and it is to be noted that the respective outline-cuts l lof any two adjacent outline-cuts substantially coincide with andpreferably are superimposed upon the nearest portion of the outline-cutdefining each adjacent blank l2. Preferably, also, the outline-cuts IIat the respective opposite ends of the sheet l0 intersect the ends ofthe said sheet, while in a transverse direction the group ofoutline-cuts II are spaced inwardly from the respective opposite sideedges, as is apparent by reference to Figs. 2 and 3.

The outline-cuts l I will normally be of V-form, and while it ispreferred that each of said outlinecuts should coincide with a portionof a next adjacent outline-cut, it is suflicient for practical purposesto have a portion of one such V-form break through into the nextadjacent V-form. The distance between the respective apices of suchV-form outline-cuts should always be less than twenty-five percent ofthe thickness of the glass being out.

After being provided with the incipient fractures defined by theoutline-cuts II the sheet 16 may be transversely flexed by any suitablemanual or automatic means to accomplish what is known in the art as theopening of the said outlinecuts, i. e., the causing of the incipientfractures to become complete fractures l3 (Fig. 4) extending from faceto face through the sheet II] or its equivalent to thus not only freethe blanks [2 from each other and from the remaining portions of thesheet I'O but also freeing the two side-strips l4 and 15 from eachother. The respective inner edges of the opposite side-strips [4' andI5, will each have a scalloped outline, as is indicated in Fig. 5.

In cases where extremely long side-strips M and [5 are produced, thesame are apt to break into two or more pieces, but this in no waydetracts from the economy of the method of the present invention.

The outline-cuts H or" their equivalent may be produced in a manner wellknown in the art, by wheel-cutters or by diamond-cutters or theirequivalent.

Inasmuch as there is substantially no uncut material between eachadjacent pair of outlinecuts H, the said outline-cuts may be' completelyopened to form the complete fractures l3, without requiring cuts inaddition to thesaid outlinecuts in order to permit the said opening, ashas been the case in the prior general practice.

In Fig. 7 is illustrated an example of prior practice in producingrounded blanks from a sheet of glass.

In the prior practice, as schematically indicated in Fig. 7, a pluralityof outline-cuts I6 are produced in a sheet of glass I? in such mannerthat each outline-cut [6' is separated from an adjacent outline-cut byan uncut web l8. Before the incipient fractures producedby theoutlinecuts It can be converted into'complete fractures to thus free theblanks ill from each other and from the adjacent material of the sheet,connetting-cuts such as 20 must be made in the various webs l8. It isfurther the custom to provide connecting-cuts such as 2| extendinginwardly from the side edges of thelsheet IT to the outline-cuts It, asis indicatedin Fig.7.

Connecting-cuts such as 2'! canonly be produced by careful manipulationof a glass cutter so as not to carry over into either of twoadjacentblanks I9, while the connecting-cuts 2'! may be made byspecially designedglass-cutting snips but here, again, with the dangerof fracturing the actual blanks which itis desired to produce.

From the foregoing it will be apparent that by adopting the simpleexpedient ofcausing one rounded outline-cut to substantially coincidewith or preferably be superimposed upon an adjacent outline-cut at theirnearest point of adjacency, the side-strips I4- and I5 are separatedfrom each other and may be readily removed to thus free theblanks l2 ortheir equivalent without injury to the said blanks.

The invention may be carried out in other specific ways than thoseherein set forth without departing from the spirit and essentialcharacteristics of the invention, and the present embodiments are,therefore, to be considered in all respect as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

We claim:

1. The method for cutting a plurality of substantially-abutting roundedblanks from a sheet of glass or the like, each of the said blanks havingits peripheral edge substantially perpendicular to the plane of the saidsheet, the said method comprising the steps of scribing the surface of asheet of glass to provide the same with a plurality ofsubstantially-abutting continuous rounded incipient-fractureoutline-cuts with each outline-cut forming a closed figure outlining a.complete blank which it is desired to produce from the said sheet andwith a portion of one outline-cut substantially coinciding with aportion of an adjacent outline-cut so as to leave substantially no uncutmaterial between coinciding portions of two adjacent outline-cuts andwith each of said outline-cuts located inwardly of the side edges of thesaid sheet thus leaving a, continuous marginal strip at each of the saidside edges, and subsequently breaking away the marginal strips of thesaid sheet outside of the said outline-cuts to free the said blanks.

2. The method for cutting a plurality of substantially-abutting roundedblanks from a sheet of glass or the like, each of the said blanks havingits peripheral edge substantially perpendicular to the plane of the saidsheet, the said method comprising the steps of: scribing the surface ofa sheet of glass to provide the same with a plurality ofsubstantially-abutting continuous rounded incipient-fractureoutline-cuts with each outline-cut forming a closed figure outlining acomplete blank which it is desired to produce from the said sheet andwith a portion of one outline-cut substantially coinciding with aportion of an adjacent outline-cut so as to leave substantially no uncutmaterial between coincidin'g portions of two-adjacent outline-cuts andwith each of said outline-cuts located inwardly from the side edges ofthe said sheet thus leaving a continuous marginal strip at each of thesaid side edges; and subsequently transversely flexing the said sheet toopen the said outline-cuts and-removing the marginal strips of the saidsheet outside of the said outline-cuts to free the said blanks.

3. The method for cutting a plurality of substantially-abutting roundedblanks from a sheet of glass or the like, each of the said blanks havingits peripheral edge substantially perpendicular to the plane of thesaid'sheet, the said method comprising the steps of: scribin the surfaceof a sheet of glass to provide the same with a, plurality of abuttingcontinuous rounded incipient-fracture outline-cuts with each outline-cutforminga'closed figure defining a complete blank which it is desired toproduce from the said sheet and with a portion of one outline-cutsuperimposed upon a portion of an adjacent outline-cut so as to leavesubstantially no uncut material between the superimposed portions of twoadjacent outlinecuts and with each of said outline-cuts located inwardlyfrom the side edges of the said'sheet thus leaving a continuous marginalstrip-at each of the said side edges; and subsequently removing themarginal strips of the said sheet outside of the said outline-cuts tofree the said blanks.

4. The method for cutting a plurality of substantially-abutting roundedblanks from a sheet of glass 01' the like, each of the said blankshaving its peripheral edge substantially perpendicular to the plane ofthe said sheet, the said method comprising the steps of: scribing thesurface of a sheet of glass to provide the same with a plurality ofabutting continuous rounded incipientfracture outline-cuts with eachoutline-cut forming a closed figure defining a complete blank which itis desired to produce from the said sheet and with a portion of oneoutline-cut superimposed upon a portion of an adjacent outlinecut so asto leave substantially no uncut material between the superimposedportions of two adjacent outline-cuts and with each of said outlinecutslocated inwardly from the side edges of the said sheet thus leaving acontinuous marginal strip at each of the said side edges; andsubsequently transversely flexing the said sheet to open the saidoutline-cuts and removing the mar- REFERENCES CITED The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 676,799 McLaughlin June 18, 1901744,245 Semmer Nov. 1'7, 1903

